Sand Hill Climbing

Our first 4x4 challenge was a sand hill climb on the
Chrysler Proving Grounds. The rutted channel ran up a ravine about 200 feet and
was covered in wet sand. First, we first tried to crawl up the hill,
but the sand was too deep and loose.

After a couple of tries, it was clear we needed more speed
to keep the tires spinning. At the top of the hill, we would have to negotiate
a tight right-hand turn to get onto an equally steep downhill trail. The
downhill section was not as sandy, and it was a great place to try the various
hill descent controls. (The Ram Power Wagon was the only player without the
feature.)

The Toyota Tacoma Baja, with its relatively wide tires and light
weight, did a pretty good job of tracking through the sand. By staying in a lower
gear, we could keep the wheels spinning, eventually inching our way to the top.
Once the shorter-wheelbase trucks found more solid ground near the top, they had
the advantage. On the way down the hill, we engaged the Toyota’s hill descent control,
and it calmly controlled our speed down to 2 mph. Once you get used to keeping
your foot away from the brake, all you have to do is steer.

The Nissan Frontier struggled a little more, as the tires
and throttle response did not seem well-matched for this event. Likewise, the
hill descent speed was a little fast. We saw 5 to 6 mph pretty quick — that may
not sound like much, but it felt unnerving on the steep slope.

The Power Wagon suffered a bit on this challenge as well, as
it took a lot of time and effort to figure out the best way to keep the tires
from sinking through the sand, stopping all progress. The truck’s extra weight
and the relatively narrow tires — not to mention finding the right gear to keep engine revs up — created a lot of
trouble for the Ram in sand. And when we did figure out the gearing and
drivetrain, the rear end lurched into a horrible axle hop that sounded like
someone was banging on the rear end with a sledgehammer. On the downhill
section (once we were able to finish our three-point turn), the extra gearing
helped control our speed, but again, the size and weight made us a little
uncomfortable as we picked up speed.

As for the SVT Raptor, it was difficult to argue with its
sharp throttle response, big horsepower and giant tires. This one had the
easiest time on the hill climb, as the Off-Road mode settings and easy-reach
center console shifter made wheel-spinning power easy to control. When you factor
in that we had the speed-sensitive front limited-slip differential and a selectable
rear locking differential in high range, the Raptor was the unanimous winner,
garnering first place and 100 points.

For event scoring, we indexed the Raptor at 100, Tacoma Baja 73, Frontier PRO-4X 67, and Power Wagon 47.

Stair-Step Navigation

This nasty piece of torturous hillside was first put in
place at the Chrysler Proving Grounds to push Jeeps to their limits and to torment
competitors into submission. The obstacle looks exactly like a set of torn-up concrete stairs, ready to make even the
most athletic off-road vehicle grovel for another way up.

The trick is not to hit the steps head-on and not allow the
vehicle to get into a hopping, bouncing rhythm; that’s when axle shafts snap.
Stiffer suspensions will struggle here, and jumpy (or sluggish) throttles or
improperly geared transmissions will punish drivers and onlookers alike. (Nobody
wants to see a truck spitting rocks at gawkers.)

Our plan of attack, previously agreed upon by the judges,
was not to bash and blast our way up this 30-yard stair climb. We wanted to
keep our progress at comfortable and reasonable speeds and let each vehicle
tell us where it struggles and where it excels. Each of us cycled in and out of each truck, drove the steps and
rotated to the next competitor.

At the end of our designated time at this event, two trucks
rose to the top again. The Tacoma Baja seemed to do pretty well with its
A-TRAC traction control, rear locker and in 4-Low. But with one of the faster crawl ratios (1st
gear x axle gear x low range), it struggled a bit when trying to look confident
and controlled — always going a touch too fast. Several times, it even got a
little sideways as it swapped wheel speed for grip on some of the slicker
sections.

The Nissan struggled in some of the same ways, suffering
from an insufficient low-range ratio (and resulting crawl ratio) that didn’t
allow the truck to go slow enough over the seemingly endless six-inch rock
faces. The Frontier’s stiff front suspension and stock wheel travel didn’t help,
either, and in the end, it didn’t look very elegant.

The Power Wagon certainly had plenty of brawn and muscle (in
the form of horsepower and lockers) for this climb, but the longer wheelbase
and front coil-link suspension made for some rough going. When we didn’t have
the front locker engaged (and, of course, we always ran with the swaybar
disconnected), we had trouble with one or the other front tires spinning. When
we engaged the front locker, we had trouble steering, navigating the steps
at angles and needing to zigzag up the challenge. Ultimately, although the
Power Wagon was quite capable, it was clawing pieces of cement off the stairs
and spitting rocks all over the place, not looking very stealthy at all.

The Raptor did quite well over this obstacle, with strong
traction at all four wheels (locker in back and aggressive limited-slip differential in
front) and good ground clearance. The front camera allowed us to see all
things necessary to comfortably walk our way, back and forth, up the steps. The
camera even shows movable guide lines (and a zoom feature) that will literally
have you putting your treads on the dime or quarter you see on the ground,
looking both elegant and stealthy. Add to that a strong, slow-going crawl ratio,
and the Raptor was the unanimous pick once again.

For event scoring, we indexed the Raptor at 100 points, Power Wagon 93, Tacoma Baja 76 and Frontier PRO-4X 66.

Rock Garden Ballet

We conducted this test outside of Flint, Mich.,
where we had the good fortune to work with a private off-road park called The
Mounds. The park charges a nominal fee for a day’s use, but it offers some
wonderful off-road trails, open sand-wash areas and even several designated and
well-maintained extreme 4x4 trails.

Our main focus centered on a 25-yard winding trail filled
with basketball-sized rocks and boulders that would let us test each truck’s
strength and flexibility to its limits. And Mother Nature gave us a bonus in
that the park was filled with mud and water holes after recent rainstorms. The
water made the rocks on our Rock Garden trail quite slick, which was just fine
by us.

The trick to this hardened minefield was keeping a steady
and even amount of throttle, allowing the tires and suspension to mold and flex
over the rocks. Much of the drive through the obstacles was determined by how
well a driver could guess at how much ground clearance was needed over some of
the larger, more pointed boulders. It wouldn’t take much to carelessly slide a
tire on the wrong side of a piece of granite and have it rotate up and puncture
through an oil pan or bend a driveshaft.

All the trucks navigated the course with various levels of
skill, but the Power Wagon’s extra ground clearance, as well as its big tires
and massive stance, seemed to really help, allowing this player to dance over
the rocks like it was a bowling ball ballet. Front and rear lockers were a big
advantage on rocks, and the flexible front end prevented most of the harsh hits
we felt in the other smaller trucks.

The Frontier had the most difficult time, taking
undercarriage and skid-plate hits every time the front wheels came off the
backside of a rock. The Tacoma Baja did better than the Nissan, but it still
struggled to keep its speed down with the low-range ratio of the transfer
case. As for the Raptor, it, too, made
short work of the Rock Garden but did struggle with its lower undercarriage
clearance heights. Its wider stance wasn’t much of an asset for our
judges, either.

For event scoring, we indexed the Power Wagon at 100 points, the Raptor 88, Tacoma Baja 80, and Frontier PRO-4X 68.

Comments

How thick are the OEM skid plates for the Raptor, Power Wagon, and Taco? I know that the OEM skids for the Frontier are useless and need to be replaced if you expect your truck to take a beating.

Posted by: phillyguy | Sep 18, 2012 11:24:21 AM

It is amusing how pickup trucks.com as well as other media outlets refer to the limited slip in the front of the Raptor. It is a torsen limited slip, which is an entirely mechanical design and does not "sense" anything. It does not "sense" speed any more so than an open differential does.

Also, you criticize the Power Wagon's wheel base and Coil spring and link suspension. You must know something extreme fourwheelers don't. The last time I checked, linked suspensions and stretched wheel bases were the ticket for extreme climbs. Although I will admit the Power Wagon's length is unwieldily, it should not have been what was hindering its performance on that particular obstacle. I really wish I could have been there to drive the trucks on that hill climb because I don't believe for a second that the Power Wagon had the hardest time with it. I cannot believe that anyone takes hill descent control seriously.Who on earth would actually use such a pointless piece of software? I have been up and down hills so steep that the oil pressure drops uncomfortably low but never have I been wishing for some type of hill control. Put the truck in its lowest gear and lightly ride the brakes enough to control yours speed. If, you feel a wheel beging to lock, let off the brakes a bit. It is SIMPLE.

I am wondering if you aired down the tires at all? It seems like the stairs were so "challenging" because the tires had too much pressure in them.

Posted by: LS.. | Sep 18, 2012 3:44:23 PM

A TorSen is torque sensitive differential. It works when in drive/drive overrun/reverse/reverse overrun. It is not speed-sensitive like a viscous coupling clutch, or gerodisc, brake-actuated traction control, etc.

What about tire pressures?
For soft, loose surfaces (like the sand hill climb) it would be advantageous to air down.
Was that done?

Dampers: We know the Raptor has special Fox bypass dampers, the rest use Bilstein. Any comment on damping rates?

Posted by: George | Sep 18, 2012 4:38:40 PM

George, I am well aware of how a Torsen limited slip functions. They consist of helical gears that are forced outward when there is a large variance in wheel speeds, and in turn bind against the carrier in order to transfer some of the force to the other side. I have taken these things apart and know exactly how they function. They are purely mechanical devices like lockers.

I am not sure if your tire pressure comment is directed at me or the author, but it is always advantageous to air your tires down when four wheeling.

Posted by: LS.. | Sep 18, 2012 5:48:10 PM

@phillyguy All the OEM "skid plates" are laughably thin. Realistically you'd need 3/16" to 1/4" thick steel to support the entire weight of the truck on pointy rocks. None of the OEMs can be expected to pack on 300 lb of armor.

Posted by: Ken Lyns | Sep 18, 2012 9:50:56 PM

@L.S. My comment was not directed at you, it was generalized.
I was hoping that the little part about the F-150 where it said "speed-sensitive" would be corrected.

The Torsen differential doesn't require any speed difference to work. That is the basis for Audi [TorSen] Quattro 1987-2012

I concur about the tire pressure. I think that 40psi cold would be a good empty [street] tire inflation for the Ram, considering the weight distribution. 80psi on the rear would be worst case towing. So 20-30 psi would be appropriate for the sand.

Posted by: George | Sep 19, 2012 6:24:22 AM

what i have noticed in the photos is that, non of the tires air was pressure were lowered, all had its on-road tyre pressure,

i cudn't believe that ram had to struggle the most on the sand hill, i had driven a toyota fortuner, 2.7ltr with pressure down to 16psi & low gear, good momentum and climbed a stepper sand dunes well without any issue.

How in the world can anyone test vehicles in sand at stock air pressures? That's ridiculous. Try dropping down to 8 - 10 psi and let's do it right. As for the other tests, again, tire pressure is key. I wonder if the people doing this test have ever been off road...

Posted by: Freefall | Dec 9, 2013 4:41:18 PM

Everybody has good points. I don't know all the techno about gearing. I kinda like they kept everything basically off the show room floor. 99% of the time the trucks are on black top anyway with fully inflated tires etc. So what the heck,let's see what they can do as they advertise on TV. They sure don't say they altered the pressure in the tires when they are going sideways slinging mud at 40 mph...
Gs

Posted by: Gary Scholze | Jan 28, 2014 6:07:37 PM

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